YZ250F 280cc Big Bore Kit 2019-2026
Turn your 2019-2026 Yamaha YZ250F into a 280cc with the BNR Motorsports Big Bore Kit.
This is a bolt-in cylinder and piston package developed for racers and performance riders looking for increased displacement, power, and torque from their YZ250F.
At the heart of the kit is our custom BNR-spec JE forged piston, designed specifically for our 280cc combination. This is not an off-the-shelf JE piston.
Kit Includes
-
280cc big bore cylinder
-
Custom BNR-spec JE forged piston
-
Piston rings
-
Piston clips
-
Top-end gaskets
-
Your choice of standard or DLC-coated wrist pin
Custom BNR / JE Piston Specs
-
3.189" (81mm) bore
-
2.110" stock stroke
-
13.8:1 compression ratio
-
JE 977M forging
-
Custom BNR piston design
-
Designed specifically for our YZ250F 280cc combination
Wrist Pin Options
Standard Wrist Pin
Our standard wrist pin option for this kit.
DLC-Coated Wrist Pin
Premium DLC-coated wrist pin featuring a low-friction, wear-resistant surface for demanding race applications.
Bolt-In 280cc Conversion
This kit is designed as a bolt-in 280cc conversion for the 2019-2026 YZ250F.
No stroker crank is required. The increased displacement is achieved through the larger bore while retaining the stock 2.110" stroke.
Vortex ECU Required
A Vortex ECU is required to properly run this 280cc combination.
Send your Vortex ECU to BNR Motorsports, and we can flash it with our calibration specifically developed for the YZ250F 280cc big bore setup.
Vortex ECU Flashing: $199.99
When sending your ECU to us, please download, complete, and include the BNR Motorsports ECU Form with your ECU:
Download BNR Motorsports ECU Form
Please Note: ECU flashing is not included with the 280cc big bore kit and must be purchased separately.
Fitment
Yamaha YZ250F
-
2019
-
2020
-
2021
-
2022
-
2023
-
2024
-
2025
-
2026
Fits 2019-2026 YZ250F models only.
This is a performance-oriented engine package. Proper fuel, ECU calibration, and engine setup are important when running this 13.8:1 compression 280cc combination.